/** 导出学生信息 */
 @Override
 public List<ExcelInfo> queryExcelInfo(StudentPageRequest studentPageRequest) {
   Map<Integer, ExcelInfo> map = new TreeMap<>();
   String schoolId = studentPageRequest.getSchoolId();
   if (schoolId == null) {
     schoolId = userService.getSchoolId(studentPageRequest.getUserId());
     studentPageRequest.setSchoolId(schoolId);
   }
   // 获取学生信息的总条数
   MStudentManager studentManager = new MStudentManager();
   BeanUtils.copyProperties(studentPageRequest, studentManager);
   List<MStudentManager> mStudentList = studentMapper.selectStudents_export(studentManager);
   for (MStudentManager students : mStudentList) {
     List<List<Object>> data;
     List<Object> row = new ArrayList<>();
     row.add(students.getRealName());
     if (students.getYears() != null) {
       int grade = ClassNameUtil.getGradeNum(students.getYears());
       ExcelInfo excelInfo = map.get(grade);
       if (excelInfo == null) {
         excelInfo = new ExcelInfo();
         data = new ArrayList<>();
         excelInfo.setData(data);
         excelInfo.setSheetName(grade + "年级");
         excelInfo.setHeaders(new String[] {"学生姓名", "所在班级", "登录账号", "上线情况"});
         excelInfo.setColumnWidth(20);
         map.put(grade, excelInfo);
       } else {
         data = excelInfo.getData();
       }
       row.add(grade + "年级" + students.getClassAliasName());
     } else {
       ExcelInfo excelInfo = map.get(0);
       if (excelInfo == null) {
         excelInfo = new ExcelInfo();
         data = new ArrayList<>();
         excelInfo.setData(data);
         excelInfo.setSheetName("无班级");
         excelInfo.setColumnWidth(20);
         excelInfo.setHeaders(new String[] {"学生姓名", "所在班级", "登录账号", "上线情况"});
         map.put(0, excelInfo);
       } else {
         data = excelInfo.getData();
       }
       row.add("无班级");
     }
     row.add(students.getUserId());
     row.add(DateUtil.getLogin_date(students.getLastLoginDate()));
     data.add(row);
   }
   return new ArrayList<>(map.values());
 }
  /** 查询学生信息分页 */
  @Override
  public PageResponse<StudentManagerDTO> queryStudentPage(StudentPageRequest studentPageRequest) {
    String schoolId = studentPageRequest.getSchoolId();
    if (schoolId == null) {
      schoolId = userService.getSchoolId(studentPageRequest.getUserId());
      studentPageRequest.setSchoolId(schoolId);
    }
    // 获取学生信息的总条数
    MStudentManager studentManager = new MStudentManager();
    BeanUtils.copyProperties(studentPageRequest, studentManager);
    long count = studentMapper.selectCount(studentManager);
    // 获取当前页的信息
    Page page = PageUtils.buildPage(studentPageRequest);
    List<MStudentManager> mStudentList =
        studentMapper.selectMStudentManagerPage(page, studentManager);
    /*
    给返回接口赋值
     */
    List<StudentManagerDTO> studentManagerDTOs = new ArrayList<>();
    for (MStudentManager mstudents : mStudentList) {
      StudentManagerDTO studentManagerDTO = new StudentManagerDTO();
      BeanUtils.copyProperties(mstudents, studentManagerDTO);
      studentManagerDTO.setLastLoginDate(
          mstudents.getLastLoginDate() == null
              ? "从未登录"
              : DateFormatUtils.format(mstudents.getLastLoginDate(), "yyyy-MM-dd HH:mm"));
      if (mstudents.getYears() != null) {
        studentManagerDTO.setClassAliasName(
            getGrade(mstudents.getYears()) + studentManagerDTO.getClassAliasName());
      } else {
        studentManagerDTO.setClassAliasName("无班级");
      }
      studentManagerDTOs.add(studentManagerDTO);
    }

    // 返回对象
    PageResponse<StudentManagerDTO> pageResponse = new PageResponse<>();
    PageUtils.buldPageResponse(studentPageRequest, pageResponse);
    pageResponse.setRows(studentManagerDTOs);
    pageResponse.setRecords(count);
    return pageResponse;
  }